Today—March 21, 2013—the much-anticipated cosmological results from the Planck satellite have been released. In a recent blog post on her own website, TED Fellow and cosmologist Renée Hlozek describes why this is a big day for astrophysics and cosmology. We asked her to explain what the excitement is all about.

“Planck is the ‘next generation’ satellite that measures the tiny fluctuations in the temperature and polarisation of the Cosmic Microwave Background (CMB) – which is light that comes from shortly after the Big Bang, and has been travelling towards us for over 13 billion years,” she says.

“Planck has been operating in space since 2009, and will dramatically increase the precision with which we can measure this radiation, which tells us about the physical conditions of the universe at very early times. We use this data to fit a cosmological model, to figure out what the universe is made of, its properties and how it is changing with time. So today is a big day because it further refines our picture of where we came from and where we are going on the grandest scales imaginable!”